1. Field of the Invention
This invention relates generally to three party calling services. More particularly, it relates to apparatus and methods to add a calling party into an existing telephone call.
2. Background of Related Art
Telephone services and advances therewith continue to be in demand in today's society. For instance, cellular telephones have provided users with the ability to place or receive telephone calls while in a car or walking down a street. Along with these advances and demands came the ability for three way conferenced calling.
Conventional three way conferenced calling enabled one party already established in a telephone call with a second party to place a second telephone call to a third party, and then to conference the two separate telephone calls together into a single three way telephone call. To enable parties having only one telephone line to initiate a three way conference call, the two separate telephone calls were conferenced at a telephone switch, e.g., private branch exchange, either at the customer's premises or at the central office of the telephone company, and then transmitted to the initiating party on the single telephone line.
FIG. 8 shows a conventional method 600 of accomplishing three way conferenced calling at a central office telephone switch, and FIGS. 9A to 9C show corresponding states of the conference call.
In particular, in step 602, a telephone call is established between party A and party B, each party having a single telephone line or only using a single telephone line of a multi-line telephone. The telephone call between party A and party B is depicted in FIG. 9A.
In step 604, at least one of the parties in the telephone call established in step 602 has three way calling service, e.g., party A. That party flashes the telephone line to indicate to the switch that the current party (e.g., party B) is to be put on hold, and a dial tone is to be presented to the flashing party, e.g., party A.
In step 606, the three way initiating party, e.g., party A, dials out to or calls a third party C, and establishes a telephone call between party A and party C. This is depicted in FIG. 9B, wherein party B is on hold and party A calls out to party C.
In step 608, party A flashes the telephone line again to indicate to the switch to conference together the telephone call to party B with the telephone call to party C, and to present the same to party A as a single telephone call. Thus, a three way call is established between parties A, B and C, as depicted in FIG. 9C.
The conventional technique of three way calling is convenient and addresses expanding needs for services to a one line telephone. However, the conventional technique requires the initiating party, e.g., party A, to call or dial the telephone number of the third party C while the other party is placed on hold.
There is thus a need for three way conferencing which allows a third party to call into an established telephone call between two other parties.